A study by the IISc Sustainability Lab has raised serious questions about the proposed 2-km, six-lane tunnel from Esteem Mall to Veterinary College via the Hebbal flyover junction in Bengaluru. The study said the tunnel could shift congestion rather than solve it, and also raised the possibility of flood risk. It said an underground Metro would be substantially more viable, provide greater network-wide relief, and cost 0.86 per passenger compared with 5.23 for the tunnel. Assessing scenarios for 2027, 2031 and 2041, the study found that while the tunnel may ease traffic at Hebbal Junction, congestion would persist on entry and exit roads near Esteem Mall and the Veterinary College, limiting its benefits. Lab convener Ashish Verma said the study report has been submitted to the Karnataka governor.